1. Field of the Invention
This invention relates to an apparatus for detecting endoscopic insertion condition which makes it possible to detect the condition of the inserted section of an endoscope when it is in the tubular body cavity to be examined.
2. Description of the Related Art
An endoscope is an apparatus equipped with a thin and flexible insert section, which is inserted into the internal section to be examined, which is a tubular body cavity, in order that the internal section to be examined may be observed and any requisite measures be taken. Tubular body cavities, e.g., the large and the small intestines, are full of twists and turns, so that it is by no means easy for the operator to know exactly where the endoscopic insert section has reached in the body cavity or what posture it has taken there.
In view of this, it has conventionally been the practice to X-ray, from the exterior, the internal section to be examined so as to detect the position, posture, etc. of the insert section in the tubular body cavity.
X-raying, however, is not entirely harmless to the human body, and thus such a method can be applied to only a limited number of body portions. Thus, the X-raying is not always an ideal detection means for detecting endoscopic inserting condition.
U.S. Pat. No. 4,176,662 discloses an apparatus for locating the position of the tip section of an an endoscope when it is in the body cavity. In accordance with this prior-art technique, a transmission section for transmitting electromagnetic waves or supersonic waves is provided at the tip section of an endoscope, and a reception antenna is provided on that portion of the endoscope which is on the outside of the body cavity. Thus, with this apparatus, electromagnetic waves or supersonic waves can be emitted from the transmission section at the tip of the endoscope and received by the reception antenna on the outside of the body cavity, thereby enabling the position of the tip section of the endoscope to be located. A problem with this prior-art technique is that a component requiring a relatively large power output (i.e., the transmission section) is inserted into the body cavity, which means, like the X-raying method mentioned above, that it is not always ideal as a means for detecting an endoscopic inserting condition.